1. Field of the Invention
This invention relates to a comminuting apparatus or shredder mill, and particularly to such an apparatus having grinding rotors with replaceable interface elements, such as hammers. Most particularly, the interface elements are interlockingly arranged in the rotors.
2. Description of the Prior Art
Traditionally, hammer mills having replaceable hammers use either one or more anchoring pins to directly secure the hammer to the rotor, see for example U.S. Pat. No. 5,484,111 (Dorscht et al.), U.S. Pat. No. 4,077,573 (Kersey et al.) or U.S. Pat. No. 5,114,985 (Inui), or use a system of clamping blocks and wedges to secure the hammer to a cutout in the rotors, see for example U.S. Pat. No. 5,320,292 (Smith).
The traditional hammer mills all share a number of apparent disadvantages and drawbacks. When the hammers get worn, it is complicated, and therefor expensive, to replace or repair this structure because either the anchoring pins or anchoring pin cover plates will have to be removed separately for each hammer to be replaced, which will pose accessibility problems when multiple rotor plates or bodies are used together, or retainers holding the clamping blocks will have to be removed to give access to the clamping blocks, with the associated problems regarding dis-assembly of the multi-piece clamp and wedge construction. Long hammer support rods are often damaged or worn, and are difficult to remove.
It is an object of the invention to mitigate and/or obviate the above mentioned disadvantages and drawbacks to provide a comminuting apparatus having interchangeable interface elements, which is easy and cheap to manufacture, assemble and service, and which provides the required shredding capacity.
One object of the invention is to provide an interchangeable interface element mounting system for the rotor, which allows the interchangeable interface elements to be easily removed, when wanted, but which provides large load carrying surfaces for the interface between interchangeable interface element and rotor body.
A further object of the invention is to provide multiple rotor bodies, which are easily joined to form rotating rolls having a plurality of axially and radially spaced interchangeable interface elements.
Still a further object of the invention is to provide a comminuting mill utilizing rotor bodies with easily replaceable interchangeable interface elements.
Yet a further object of the invention is to provide solid rotor bodies and interface elements, to increase the rotating mass factor and thus the potential energy of the system.
In the invention, an interchangeable and interlocking interface element and rotor assembly for rotary hammermills, comprises at least two rotor bodies, a plurality of interchangeable interface element mounting cut-outs arranged substantially radially in the at least two rotor bodies and a plurality of peripheral mounting holes arranged to receive rotor body bundling means to hold the at least two rotor bodies fixedly against each-other and to prevent the plurality of interchangeable interface elements to exit from the interchangeable interface element mounting cut-outs, and a plurality of interchangeable interface elements arranged to be mountable in the interchangeable interface element mounting cut-outs. Each of the plurality of interchangeable interface elements have a substantially oblong and planar shape, a bottom end shaped to interlock with the interchangeable interface element mounting cut-outs, a leading edge facing the direction of rotation of the rotors, a trailing edge facing the side opposite to the direction of rotation, and interchangeable interface element tip mounting means, arranged in an upper mounting portion of each plurality of interchangeable interface elements. The interchangeable interface elements further have a bottom portion with a generally rounded surface arranged to cooperate with a generally rounded bottom portion of the interchangeable interface element mounting cutouts, a heel portion facing the direction of rotation and shaped to cooperate with a recess portion of the interchangeable interface element mounting cutouts so that during insertion of an individual interchangeable interface element in one interchangeable interface element mounting cut-out, by inserting the bottom portion first, the generally rounded surface is slidable into a relief recess portion of the interchangeable interface element mounting cut-outs, permitting the heel portion to clear the protruding portion and the interchangeable interface element to be seated with the bottom portion in the generally rounded bottom portion of the interchangeable interface element mounting cut-outs locking the individual interchangeable interface element from movement in a radial direction in the at least two rotor bodies, the plurality of interchangeable interface elements further having a first force absorbing surface, arranged on the trailing edge, and a second force absorbing surface, arranged on the leading edge, and interchangeable interface element securing fasteners, arranged to receive the rotor bundling means for securing the plurality of interchangeable interface elements axially to the at least two rotor bodies.
The rotors preferably have a substantially cylindrical outer edge, but alternatively could be square, hexagon shaped or similar.
The rotor bundling means preferably comprise rotor bolts and rotor nuts.
The at least two rotor bodies are preferably fixably arranged on a rotatable common shaft running through central mounting holes in the at least two rotor bodies.
The at least two rotor bodies are preferably attached to the rotatable shaft using a pair of conical bushings arranged to clamp the rotatable shaft to the at least two rotor bodies.
The plurality of interchangeable interface elements preferably have replaceable interchangeable interface element tips arranged at an outer end of the plurality of interchangeable interface elements facing the leading edge.
The assembly may comprise interchangeable interface elements arranged in straight rows or interchangeable interface elements arranged along helical curves.
The rotatable shaft is preferably rotated by a hydraulic motor, an electric motor or an internal combustion engine.
Thus, no load carrying pins are used, the interchangeable interface element holder is instead shaped to be slidable into a cutout in the rotor and held in the cutout by a heel formed at a lower part of the interchangeable interface element holder. The heel is held by a corresponding protruding portion of the cutout.
Further features of the invention will be described or will become apparent in the course of the following detailed description.